In Korean cuisine, live octopus is quite common. One dish I've tried is where they fish out a baby octopus from the tank and chop it up right in front of you, then add a dash of soju (korean liquor) and sprinkle some ginger, then serve. Tentacles still ferociously wrinkling about even after 20 minutes. Another sort of dish (more like street food) is where they serve live octopus on a stick, literally grabbing a baby octopus, fresh from the tank, grab a wooden skewer, and let the octopus wrap itself around it. To "eat" it, you just sort of place the whole thing in your mouth, head first, and swallow it straight away.

Most seafood can be eaten fresh and raw really, especially shellfish and crustaceans.